Mobile radio communications system having a supervising radio transmitting station for transmitting a reference synchronizing signal to a first and second base stations via a radio link

Abstract

A radio communication system having a plurality of base stations, each forming a radio zone, and a plurality of mobile stations connected to those base stations in a time-division multiplexing manner via digital radio circuitry that time-division multiplexes a plurality of time slots for those base stations, comprising at least one supervising radio transmitting station for transmitting a reference synchronizing signal to a first and a second base station of the plurality of base stations via radio circuitry, the reference synchronizing signal being used in establishing synchronous relationship between the first and second base stations, receiving section installed in each of the first and second base stations, for receiving the reference synchronizing signal from the supervising radio transmitting station via radio circuitry, and synchronizing section installed in each of the first and second base stations, for establishing synchronous time-slot relationship in the digital circuitry between those base synchronizing stations and the mobile stations, based on the reference signal received by the receiving section.

What is claimed is: 
     
       1. A radio communication system comprising: a plurality of base stations, each forming a radio zone;   a plurality of mobile stations, wherein signals are transmitted between said plurality of mobile stations and said plurality of base stations in a time-division multiplexing manner over a first radio link established using digital radio circuitry that time-division multiplexes a specific time interval into a plurality of time slots;   at least one supervising radio transmitting station for transmitting a reference synchronizing signal to a first and a second base station of said plurality of base stations via a second radio link, said reference synchronizing signal being used in establishing a synchronous relationship between said first and second base stations;   receiving means provided in each of said first and second base stations, for receiving said reference synchronizing signal from said supervising radio transmitting station via said second radio link; and   synchronizing means provided in each of said first and second base stations, for establishing a synchronous time-slot relationship in said digital radio circuitry between said first and second base stations and said mobile stations, based on said reference synchronizing signal received by said receiving means,   wherein said digital radio circuitry includes a frequency variable control unit for establishing a transmission frequency at which a mobile station and a base station transmit signals over the first radio link based on said reference synchronizing signal.   
     
     
       2. The radio communication system according to claim 1, wherein said frequency variable control unit establishes the transmission frequency based on the transmitting frequency of said at least one supervising radio transmitting station. 
     
     
       3. The radio communication system according to claim 1, wherein said frequency variable control unit establishes the transmission frequency based on information contained in the reference synchronizing signal. 
     
     
       4. A radio communication system comprising: a plurality of base stations, each forming a radio zone;   a plurality of mobile stations, wherein signals are transmitted between said plurality of mobile stations and said plurality of base stations in a time-division multiplexing manner over a first radio link established using digital radio circuitry that time-division multiplexes a specific time interval into a plurality of time slots, said plurality of mobile stations including a first and a second mobile station communicating with different ones of said plurality of base stations;   at least one supervising radio transmitting station for transmitting a reference synchronizing signal to said first and second mobile stations via a second radio link, said reference synchronizing signal being used in establishing a synchronous relationship between said first and second mobile stations;   receiving means provided in each of said first and second mobile stations, for receiving said reference synchronizing signal from said supervising radio transmitting station via said second radio link; and   synchronizing means provided in each of said first and second mobile stations, for establishing a synchronous time-slot relationship in said digital radio circuitry between said first and second mobile stations and said base stations, based on said reference synchronizing signal received by said receiving means.   
     
     
       5. The radio communication system according to claim 4, wherein said supervising radio transmitting station has the same communicating functions of transmitting and receiving as those of said first base station and said second base station used in a paging system for transmitting a paging signal to a paging apparatus. 
     
     
       6. The radio communication system according to claim 4, further comprising a second supervising radio transmitting station, wherein said at least one supervising radio transmitting station and said second supervising radio transmitting station transmit said reference synchronizing signal at the same frequency to said first and second mobile stations. 
     
     
       7. The radio communication system according to claim 4, wherein said at least one supervising radio transmitting station transmits said reference synchronizing signal to said first and second mobile stations at prescribed periodic intervals. 
     
     
       8. The radio communication system according to claim 4, wherein said at least one supervising radio transmitting station transmits said reference synchronizing signal at first periodic intervals to said receiving means via said second radio link. 
     
     
       9. The radio communication system according to claim 8, wherein said receiving means further receives a signal from said base station at second periodic intervals shorter than said first periodic intervals. 
     
     
       10. A radio communication system comprising: a plurality of base stations, each forming a radio zone;   a plurality of mobile stations, wherein signals are transmitted between said plurality of mobile stations and said plurality of base stations in a time-division multiplexing manner over a first radio link established using digital radio circuitry that time-division multiplexes a specific time interval into a plurality of time slots;   at least one supervising radio transmitting station for transmitting a reference synchronizing signal via a second radio link to a first one of said plurality base stations and a first one of said plurality of mobile stations communicating with a second base station different from said first base station, said reference synchronizing signal being used in establishing synchronous relationship between said first base station and said first mobile station;   receiving means provided in each of said first base station and said first mobile station, for receiving said reference synchronizing signal from said supervising radio transmitting station via said second radio link; and   synchronizing means provided in each of said first base station and said first mobile station, for establishing a synchronous time-slot relationship in said digital radio circuitry between said first base station and a second one of said plurality of mobile stations communicating with said first base station and said first mobile station communicating with said second base station, based on said reference synchronizing signal received by said receiving means.   
     
     
       11. The radio communication system according to claim 10, wherein said supervising radio transmitting station has the same communicating functions of transmitting and receiving as those of said first base station and said second base station used in a paging system for transmitting a paging signal to a paging apparatus. 
     
     
       12. The radio communication system according to claim 10, further comprising a second supervising radio transmitting station, wherein said at least one supervising radio transmitting station and said second supervising radio transmitting station transmit said reference synchronizing signal at the same frequency to said first base station and said first mobile station. 
     
     
       13. The radio communication system according to claim 10, wherein said supervising radio transmitting station transmits said reference synchronizing signal to said first base station and said first mobile station at prescribed periodic intervals. 
     
     
       14. The radio communication system according to claim 10, wherein said supervising radio transmitting station transmits said reference synchronizing signal at prescribed periodic intervals to said receiving means via said second radio link. 
     
     
       15. The radio communication system according to claim 14, wherein said receiving means installed in said first mobile station further receives a signal from said second base station at second periodic intervals shorter than said first periodic intervals. 
     
     
       16. A radio communication system comprising: a plurality of base stations, each forming a radio zone;   a plurality of mobile stations, wherein signals are transmitted between said plurality of mobile stations and said plurality of base stations in a time-division multiplexing manner over a first radio link established using digital radio circuitry that time-division multiplexes a specific time interval into a plurality of time slots;   at least one supervising radio transmitting station for transmitting a reference synchronizing signal to a first and a second base station of said plurality of base stations via a second radio link, said reference synchronizing signal being used in establishing a synchronous relationship between said first and second base stations;   receiving means provided in each of said first and second base stations, for receiving said reference synchronizing signal from said supervising radio transmitting station via said second radio link; and   synchronizing means provided in each of said first and second base stations, for establishing a synchronous time-slot relationship in said digital radio circuitry between said first and second base stations and said mobile stations, based on said reference synchronizing signal received by said receiving means,   wherein said first and second base stations and said mobile stations are synchronized with each other, and communications are made at the same frequency and in different time slots between said first and second base stations and said mobile stations which have been synchronized with each other.   
     
     
       17. The radio communication system according to claim 16, wherein said supervising radio transmitting station has the same communicating functions of transmitting and receiving as those of said first base station and said second base station used in a paging system for transmitting a paging signal to a paging apparatus. 
     
     
       18. The radio communication system according to claim 16, further comprising a second supervising radio transmitting station, wherein said at least one supervising radio transmitting station and said second supervising radio transmitting station transmit said reference synchronizing signal at the same frequency to said first and second base stations. 
     
     
       19. The radio communication system according to claim 16, wherein said supervising radio transmitting station transmits said reference synchronizing signal to said first and second base stations at prescribed periodic intervals. 
     
     
       20. The radio communication system according to claim 16, wherein said supervising radio transmitting station transmits said reference synchronizing signal at prescribed periodic intervals to said receiving means via said second radio link.